The invention relates to warning signs and barricades of the type used beside roadways during construction to provide information or to channelize traffic. Conventionally, such devices are made of wood and/or metal and have an inherently high center of gravity. To make them stable, sand bags are usually laid over their cross bars or stacked around their bases. Unfortunately, the sand bags are often not used, or they break or are stolen, leaving the warning device susceptible to being blown over by the wind or by the suction induced by passing vehicles. Once a device falls, it can of course provide no warning and it also presents a danger in that it can be struck by a vehicle, causing damage to itself as well as to the vehicle and sometimes to the occupants therein.
A folding hollow plastic barricade which overcomes the problems of the prior art wood and metal barricades is disclosed in our copending U.S. Pat. application Ser. No. 488,531 filed July 15, 1974, now U.S. Pat. No. 3,880,406. It would be most advantageous if the improvements in safety provided by our folding plastic barricade could be extended to other types of warning devices, including non-folding barricades. It is the object of the present invention to provide a series of warning devices, each utilizing a common hollow plastic support member, and which are safer than prior art wood and/or metal devices; are less susceptible to being blown over by the wind; are lighter in weight and easier to carry; and are in most cases undamaged by impact.